Botulism due to Injection Drug Use

Audience This scenario was developed to educate emergency medicine residents on the diagnosis and management of wound botulism secondary to injection drug use. Introduction Botulism is a relatively rare cause of respiratory failure and descending weakness in the United States, caused by prevention of presynaptic acetylcholine release at the neuromuscular junction. This presentation has several mimics, including myasthenia gravis and the Miller-Fisher variant of Guillain-Barré. It may be caused by ingestion of spores (infant), ingestion of pre-formed toxin (food-borne), formation of toxin in vivo (wound-associated cases), through weaponized sources, or through inappropriately administered injections (iatrogenic). Cases of black tar heroin injection have been associated with botulism. Regardless of the etiology, prompt assessment and support of respiratory muscle strength and ordering antidotal therapy is key to halting further muscle weakness progression. Educational Objectives At the conclusion of the simulation session, learners will be able to: 1) Identify the different etiologies of botulism, including wound, food-borne, infant, iatrogenic, and inhalational sources, 2) describe the pathophysiology of botulism toxicity and how it prevents presynaptic acetylcholine release at the neuromuscular junction, 3) develop a differential for bilateral descending muscle weakness, 4) compare and contrast presentations of myasthenia gravis, botulism, and the Miller-Fisher variant of Guillain-Barré syndrome, 5) describe measurement of neurologic respiratory parameter testing, such as negative inspiratory force, 6) outline treatment principles of wound-associated botulism, including antitoxin administration, wound debridement, tetanus vaccination, and evaluation for the need of antibiotics, and 7) identify appropriate disposition of the patient to the medical intensive care unit (ICU). Educational Methods This session was conducted using high-fidelity simulation, followed by a debriefing session and lecture on the diagnosis, differential diagnosis, and management of botulism secondary to injection drug use. Debriefing methods may be left to the discretion of participants, but the authors have utilized advocacy-inquiry techniques. This scenario may also be run as an oral board case. Research Methods Our residents are provided a survey at the completion of the debriefing session so they may rate different aspects of the simulation, as well as provide qualitative feedback on the scenario. Results Sixteen learners completed a feedback form. This session received all six and seven scores (consistently effective/very good and extremely effective/outstanding, respectively) other than three isolated five scores. The form also includes an area for general feedback about the case at the end. Illustrative examples of feedback include: “Really awesome debrief, breakdown of pathophysiology and clinical applications. Great work!”; “Great case with awesome learning points,” and “Loved this session. Rare case but very great learning.” Specific scores are available upon request. Discussion This is a cost-effective method for reviewing botulism diagnosis and management. The case may be modified for appropriate audiences, such as using classic illness scripting (eg, ingestion of canned foods). We encourage readers to utilize a standardized patient to demonstrate extraocular muscle weakness and bulbar symptoms to increase psychological buy-in. Topics Medical simulation, botulism, toxicologic emergencies, toxicology, neurology, emergency medicine.


Linked objectives and methods:
Patients with botulism require prompt recognition and treatment with antitoxin in order to slow progression to respiratory failure. After this scenario, providers will be able to describe the different causes of botulism toxicity (objective 1), the pathophysiology of botulism toxicity (objective 2) and compare and contrast different neuromuscular weakness pathologies that may present similarly (objectives 3 and 4). Because a neuromuscular cause of descending weakness is suspected, neurologic respiratory parameters such as a negative inspiratory force and forced vital capacity should be obtained to assess the current trajectory of respiratory failure (objective 5). Once botulism is established as a potential cause of weakness, the process of ordering antitoxin should be arranged, as well as ancillary care such as wound debridement, tetanus vaccination, and assessing need for antibiotics (objective 6) before being admitted in the medical ICU for further respiratory monitoring and management (objective 7). Objectives were tracked by facilitators taking notes during the simulation scenario for the subsequent debriefing discussion.
This simulation scenario allows learners to reinforce botulism diagnostic and management skills in a psychologically-safe learning environment, and then receive formative feedback on their performance.

Recommended pre-reading for instructor:
We recommend that instructors review literature regarding botulism, including presenting signs/symptoms, diagnosis, and management. Suggested readings include materials listed under the "References/suggestions for further reading" section below.

Results and tips for successful implementation:
This simulation was written to be performed as a high-fidelity simulation scenario, but also may be used as a mock oral board case. The case was written for emergency medicine residents within the setting of an emergency department (ED) with a stroke center designation; however, neurology will be unavailable for consultation if called.
Starting the case off with the nurse stating that the patient was a stroke alert allowed for residents to work through triage cueing and momentum bias. Depending on the experience of the learners, this may be left in or omitted at the facilitator's discretion.
Botulism due to injection drug use was chosen due to the uncommon presentation of wound botulism. Ultimately, only one group out of nine voiced the diagnosis of botulism during the scenario, but no one ordered the antitoxin. About half of the groups voiced a possible differential diagnosis of myasthenia gravis. During debriefing, residents gave positive feedback regarding the review of neuromuscular disorders with comparing and contrasting their clinical presentations. Facilitators may choose to use a classic illness script such as eating homemade canned foods or an infant who became constipated and weak after being fed unpasteurized honey.

List of Resources:
Abstract

Objectives:
By the end of this simulation session, learners will be able to: 1. Identify the different etiologies of botulism (wound, food-borne, infant, iatrogenic, inhalational) 2. Describe the pathophysiology of botulism toxicity 3. Develop a differential for bilateral descending muscle weakness 4. Compare and contrast presentations of myasthenia gravis, botulism, and the Miller-Fisher variant of Guillain-Barré syndrome 5. Describe measurement of neurologic respiratory parameter testing 6. Outline treatment principles of wound-associated botulism, including antitoxin administration, wound debridement, tetanus vaccination, and evaluation for the need of antibiotics 7. Identify appropriate disposition of the patient to the medical intensive care unit (MICU). 8.
Our scenario began with the patient demonstrating an earlier disease course with extraocular muscle and bulbar weakness rather than dyspnea, but then progressed to descending paralysis and early respiratory muscle weakness. We did not want to focus on respiratory failure in neuromuscular disease and how this may affect paralytic dosing; however, facilitators may elect to edit the case to emphasize these points.
We found that putting up a picture of ptosis and mydriasis emphasized that in the confederate's ptosis exam, but it was still difficult to appreciate mydriasis on the picture. Subsequently, we had the confederate patient state, "I don't know why my pupils are so large," when his eyes were examined.
One of our clinical respiratory therapists participated in the case and demonstrated how to obtain respiratory parameters (negative inspiratory force, vital capacity) when the learners requested these, which was well-received.
Our residents are provided a survey at the completion of the debriefing session so they may rate different aspects of the simulation, as well as provide qualitative feedback on the scenario. The local institution's simulation center's electronic feedback form is based on the Center of Medical Simulation's Debriefing Assessment for Simulation in Healthcare (DASH) Student Version Short Form 1 with the inclusion of required qualitative feedback if an element was scored less than a six or seven.
Sixteen learners completed a feedback form. This session received all six and seven scores (consistently effective/very good and extremely effective/outstanding, respectively) other than three isolated five scores. The lowest average score was tied at 6.63 for "Before the simulation, the instructor set the stage for an engaging learning experience," and "The instructor identified what I did well or poorly -and why." The highest average score was 6.94 for "The instructor provoked in-depth discussions that led me to reflect on my performance." The form also includes an area at the end for general feedback about the case. Illustrative examples of feedback include: "Really awesome debrief, breakdown of pathophysiology and clinical applications. Great work!"; "Great case with awesome learning points," and "Loved this session. Rare case but very great learning." Specific scores are available upon request.

Case Description & Diagnosis (short synopsis):
Patient is a 37-year-old male who presents to triage by private vehicle with two hours of blurry vision. Upon further questioning in triage, he disclosed four days of difficulty speaking. Triage called a stroke alert and requested an immediate evaluation prior to going to the computed tomography (CT) scanner. If asked to go to CT before a neurologic physical exam has been performed, the CT scanner is currently busy with trauma patients.
Participants should request a point-of-care glucose and perform a full neurologic exam on the patient, which should reveal symmetric ptosis and slurred speech. Exposure of the patient's arms reveal bilateral track marks with surrounding erythema. When directly questioned, patient discloses injection drug use. At this point, participants should suspect other differentials such as myasthenia gravis or botulism. The patient will experience worsening bradycardia and develop dyspnea with delays in diagnosis or initiation of treatment; however, respiratory parameters should be reassuring against immediate need for intubation. Poison control or the health department should be contacted to obtain antivenom to treat for botulism. The patient should ultimately be dispositioned to the medical intensive care unit. How the scene unfolds: Patient is a 37-year-old male who presents to triage by private vehicle with two hours of blurry vision. Upon further questioning in triage, he disclosed four days of difficulty speaking. Triage called a stroke alert and requested an immediate evaluation prior to going to the CT scanner. If asked to go to CT before a neurologic physical exam has been performed, the CT scanner is currently busy with trauma patients.

Equipment or Props
Patient's vitals are initially stable. Participants should request a point-of-care glucose and perform a full neurologic exam on the patient, played by a confederate actor, which should reveal symmetric ptosis and slurred speech. When the eyes specifically are examined, participants are shown a picture of a patient with ptosis and mydriasis. Exposure of the patient's arms reveal bilateral track marks with surrounding erythema. When directly questioned, patient discloses injection drug use. At this point, participants should suspect other differentials such as myasthenia gravis or botulism. The patient will experience worsening bradycardia and develop dyspnea with mild hypoxia with delays in diagnosis or initiation of treatment at minutes six and twelve; however, respiratory parameters should be reassuring against immediate need for intubation, and patient will still be able to speak in complete sentences without somnolence.
Participants may obtain a CT scan of the head or perform a lumbar puncture to evaluate for the albuminocytologic dissociation seen with myasthenia gravis; however, labs and imaging will be largely unrevealing. Neurology will be initially unavailable for consultation, but if called after CT head is interpreted, they will remark that the patient does not sound like a tissue plasminogen activator (tPA) candidate and leave the conversation abruptly. Poison control or the health department should be contacted to obtain antivenom to treat for botulism. The patient should ultimately be dispositioned to the medical intensive care unit. Labs, EKG should be ordered.
CT will be available to the learners once a neurologic exam has been performed.
If the team recognizes botulism and orders antitoxin by minute 6, vitals remain unchanged from vitals (B).
If the team does not order the antitoxin by minute 6, bradycardia worsens and patient develops dyspnea/hypoxia (C). The patient can also say, "Hey, I can't shrug my shoulders," and give a weak/minimal shrug to demonstrate descending muscle weakness.
If team doesn't order a CT scan, nursing will remind them that a stroke alert was called and ask them if they still want to go to the CT scanner.
If neurology is called before CT head is interpreted by the team, the nurse will tell the participants that the neurologist is busy and therefore unavailable for consultation at this time.
If neurology is called after CT head is interpreted by the team, neurology will remark that the patient does not sound like a tPA candidate and leave the conversation abruptly Should order neurologic respiratory parameters and order the antitoxin If team orders respiratory parameters and antitoxin, vitals remain unchanged (C).
If respiratory parameters are not ordered by minute 12, patient becomes more dyspneic with shallow breathing (D).
If antidote is not ordered by minute 12, vitals worsen more markedly (E).
Case ends after antidote is ordered, respiratory parameters obtained, and the MICU is contacted for admission (or minute 15/facilitator's discretion).
If the team does not ask to call for admission, the nurse should prompt, "We need this bed; triage is full. What are we doing for dispo?"  CDC's key features: • absence of fever